10 EOMs

Question 1

All recti muscles originate in the ________ __ ____ at the posterior orbital apex. Located anterior to optic foramen

Answer 1

Annulus of Zinn (common tendinous ring)

Question 2

The recti muscles insert relatively more ________ to the globe and then gradually more posterior portion insertions as one moves around the ____________ limbus. What’s the order of the insertion pattern? Name of pattern?

Answer 2

Anterior. Corneoscleral

Medial->inferior-> lateral->superior

Spiral of TIllaux

Question 3

What EOM originates at the orbital surface of lesser wing of sphenoid bone? Innervated by upper division CN III. Action is to elevate eye lid

Answer 3

Levator palpebrae superioris

Question 4

Which EOM passes beneath levator, above SO on globe. Action is to elevate. Originates in annulus Zinn. Innervated by superior division of CN III. Blood supply by superior lateral muscular branch of ophthalmic artery

Answer 4

Superior rectus

Question 5

Which EOM is the LARGEST? Primary action is to ADduct and originate in annulus of zinn. It inserts 5.5mm posterior to limbus anterior medial globe. Innervated by CN III and supplied by inferior medial muscular branch of ophthalmic artery

Answer 5

Medial rectus

Question 6

What are conjugate movement of both eyes in the SAME direction?

Tested with both eyes open and asking the patient to follow a target in each direction of gaze.

Answer 6

Versions

Question 7

The superior division of CN III innervates?

Inferior division of CN III innervates?

CNVI?

CN IV?

Answer 7

SR

MR, IR, IO

LR

SO

Question 8

Which EOM depresses, extorts and adducts, originates in superior and inferior annulus of Zinn, and greater wing of sphenoid bone? Innervated by inferior division of CN III. Blood supply is the infraorbital artery and inferior medial muscular branch of ophthalmic artery

Answer 8

Inferior rectus

Question 9

Which EOM is innervated by CN VI?

What’s the blood supply of this EOM?

Origin?

Insertion?

Primary and secondary actions?

Answer 9

Lateral rectus

Lacrimal artery and superior lateral muscular branch of ophthalmic

Superior and inferior annulus of Zinn

ABducts. No secondary

Posterior to limbus anterior lateral globe

LR6 SO4

Question 10

Which EOM is the LONGEST and THiNNEST?

Primary action:
Secondary:

Origin:

Innervation:

Blood supply:

Answer 10

Superior oblique

Intorts.
Depresses, ABducts

Lesser wing of sphenoid

Uses a pulley (passes anterior through trochlea)

CN IV. LR6SO4

Superior lateral muscular branch of ophthalmic

Question 11

Which EOM is the SHORTEST?

Primary action:
Secondary:

Origin:

Innervation:

Blood supply:

Answer 11

Inferior oblique

Extorts
Elevates, ABducts

Maxillary bone (only EOM to originate in ANTERIOR orbit)

CN III

Infraorbital artery and inferior medial muscular branch of ophthalmic artery

Question 12

What do check ligaments do?

Answer 12

STOPS excessive movement

Question 13

Name the EOMS associated with the ductions:

ABduction

Extorsion

Elevation

Intorsion

ADDuction

Depression

Answer 13

LR

IO

SR

SO

MR

IR

Question 14

What is conjugate movement of both eyes in the same direction? Tested by following the 9 cardinal positions of gaze

What’s movement involving one eye? 6 movements

Answer 14

Versions

Ductions

Question 15

The EOM’s are innervated by the following:

The ________ division of CN III innervates the: MR, IR, IO. While the ________ division of CN III innervates the SR.

CN VI innervates __

CN __ innervates SO

Answer 15

Inferior. Superior

LR

IV 4